EXPERIMENT 6 – RNA ISOLATION AND RT-PCR ANALYSIS ...

RNA Isolation and RT-PCR Analysis (Gene TWO)

6.1

EXPERIMENT 6 – RNA ISOLATION AND RT-PCR ANALYSIS (GENE TWO)

Purpose: To determine the mRNA accumulation pattern of the gene of interest in wild

type and mutant Arabidopsis siliques.

OVERVIEW OF RT-PCR STRATEGY

I. ISOLATION OF TOTAL RNA USING QIAGEN RNEASY PLANT MINI KIT II. SYNTHESIZING FIRST STRAND cDNA USING REVERSE

TRANSCRIPTASE (REVERSE TRANSCRIPTION or RT) III. CARRYING OUT PCR AMPLIFICATION (RT-PCR) ANALYSIS


6.2

OVERVIEW OF RT-PCR (Based on RT-PCR Technical Note from Invitrogen)

Cells or Tissue or Organ RNA Isolation AAAAAA(A)n RNA 5' 5' AAAAAA(A)n + tRNAs 5' AAAAAA(A)n + rRNAs

cDNA Synthesis

RT AAAAAA(A)n TTTTTT-5' AAAAAA(A)n

TTTTTT-5' AAAAAA(A)n TTTTTT-5' PCR Amplification PCR TTTTTT-5' Fw AAAAAA-3' Rv >107 DNA Molecules


6.3

I. ISOLATION OF TOTAL RNA USING QIAGEN RNEASY PLANT MINI KIT

Purpose: To extract total RNA from siliques to study gene expression. You will perform

RT-PCR on total RNA isolated from siliques from wild type and mutant plants in

order to determine if the T-DNA insertion causes a null mutation (i.e. no mRNA is

expressed for the gene of interest).

References: RNeasy Plant Mini Kit Protocol (Qiagen; see Appendix 1G)

Sambrook, J., Fritsch, E.F. and Maniatis, T., 1989. In: (Second Edition),

Molecular Cloning: A Laboratory Manual. Cold Spring Harbor

Laboratory Press, Cold Spring Harbor, New York. (ISBN 978-

0879693091)

FREQUENTLY ASKED QUESTIONS

PROCEDURE

A. Grinding Tissue for RNA Extraction B. RNA Isolation

C. Removing Contaminating Genomic DNA from Total RNA Solutions Using RNase-free DNase

D. Determining the Quality of Isolated Total RNA Before and After DNase

Treatment Using Capillary Gel Electrophoresis


6.4

FREQUENTLY ASKED QUESTIONS

(Taken from Qiagen RNeasy Plant Mini Handbook June 2001; see Appendix 1G)

6. What is the maximum amount of starting material? 100 mg

7. Is the yield of total RNA the same for the same amount of starting material for

different plant species? No, the yield varies for different plant species.

8. Which lysis buffer can be used for plant materials? q Buffer RLC (Guanidine Hydrochloride) is used for endosperm and tissues

containing endosperm (e.g., siliques). Although Guanidine Isothiocyanate is

better at cell disruption and denaturation than Guanidine Hydrochloride,

Guanidine Isothiocyanate can cause solidification of endosperm samples,

making extraction of RNA impossible.

q Buffer RLT (Guanidine Isothiocyanate) is used for all plant tissues except

endosperm and tissues containing endosperm (e.g., siliques).

9. Is total RNA isolated with RNeasy kit free of genomic DNA? No, most (but not all) of DNA is eliminated. Therefore, if total RNA will be used

for downstream application such as Reverse-transcription-PCR (RT-PCR), then

DNase treatment must be carried out for the total RNA.

10. What is the role of QIAshredder homogenizer?

It simultaneously removes insoluble material and reduces the viscosity of the lysates by disrupting gelatinous material.

C. Grinding Tissue for RNA Extraction

Note: Grinding Tissue for RNA Extraction will be carried out by the Teaching

Assistants (TAs).

Materials Needed:


6.5

Ø Key to the Plant Growth Center Ø BruinCard with access to PGC Ø Plant layout charts indicating plants homozygous or heterozygous for the T-DNA Ø Ice bucket Ø Kimwipes Ø A squirt bottle of 100% Ethanol solution Ø Forceps Ø Liquid Nitrogen (from storeroom in Life Sciences Building) Caution: It is very cold

(at least -210˚C). Avoid getting frostbite. Ø Dewar flask or Styrofoam box Ø Diethyl Pyrocarbonate (DEPC). Caution: DEPC is suspected to be carcinogenic and

corrosive. Therefore, hand with care! DEPC inhibits RNase. Ø 500 mL of freshly prepared 0.1% DEPC-treated water (non-autoclaved) for cleaning

all equipment Ø Autoclaved, DEPC-treated porcelain mortar and pestle Ø Autoclaved, DEPC-treated, blue micropestles Ø Qiagen RNeasy Plant Mini Kit: (Cat. #74904 for 50 extractions) Ø β-mercaptoethanol. Caution: Work in the fume hood because this chemical has very

bad odor. Ø Black ultra-fine sharpie Ø Autoclaved, DEPC-treated spatulas Ø RNase-free 14 mL disposable centrifuge tubes Ø RNase-free 1.5 mL microcentrifuge tubes Ø Racks for microcentrifuge tubes Ø Scale

Attention: Before isolating RNA, use Kimwipes wetted with freshly prepared non-

autoclaved DEPC treated water to clean all equipment (pipette sets, pipet stand,

microcentrifuge-tube racks, micro centrifuges and rotors, test-tube racks, pens and

sharpies, pipet tip boxes, microcentrifuge tube containers) to be used in isolating

RNA.

PROCEDURE

1. Get ice from the icemaker.

2. Label the white area on the side of ONE RNase-free 14 mL centrifuge tube “WT Siliques.” Label SIX 1.5 mL microcentrifuge tubes with the name of each mutant

line. Chill on ice.

3. Go to the Plant Growth Center.


6.6

4. Use a piece of Kimwipes to clean the forceps with ethanol. Note: Two sets of forceps

are used per plant. The forceps must be cleaned after the collection of siliques from

each line to avoid contamination.

5. Working quickly, use forceps to harvest siliques from wild type Arabidopsis

Columbia-0 siliques and siliques from each mutant line. Select siliques from a plant

homozygous for T-DNA if available, otherwise use siliques from a heterozygous

plant. Select siliques that contain seeds with embryos ranging from globular to

torpedo stage. Immediately, place siliques in the chilled, labeled tubes. Note: Clean

the forceps with ethanol before collecting from a new line.

6. Return to the lab.

7. Immediately chill the samples either on crushed dry ice or in a Dewar flask or

Styrofoam box containing liquid nitrogen (filling up to one-third of the Styrofoam

box).

8. Chill an RNase-free spatula in a Dewar flask containing liquid nitrogen.

9. Chill the mortar and pestle with liquid nitrogen until liquid nitrogen is not bubbling

out vigorously.

10. Place WT siliques in the chilled mortar containing liquid nitrogen.

11. Using the pestle, grind the frozen tissue to a powder in liquid nitrogen. Note: It is best

to grind the tissue when the last drop of liquid nitrogen has just evaporated. Grind

quickly. Do not let the tissue thaw. Repeat this step until there are no more chunks of

tissue present.

12. Add some liquid nitrogen to the mortar and quickly pour the tissue and liquid

nitrogen to a chilled, labeled 14 mL tube set on crushed dry ice or in liquid

nitrogen. You may use the chilled spatula to get the powder into the tube.

13. Lightly place the cap on top of the 14 mL tube to allow the liquid nitrogen within the

tube to evaporate, but do not allow the tissue to thaw. Note: You may also place the

tube in a -70°C freezer to allow the evaporation of liquid nitrogen.

14. For the mutant samples, grind the siliques in the 1.5 mL microcentrifuge tubes

chilled in liquid nitrogen with the blue micropestles that have been treated with

DEPC, autoclaved and chilled in liquid nitrogen. Use a new micropestle for each

sample to avoid contamination. Note: Grind quickly and place the tube back in the


6.7

liquid nitrogen. Do not let the tissue thaw. Repeat this step until there are no more

chunks of tissue present.

15. Label TWELVE 1.5 mL microcentrifuge tubes with the sample names. Set the tubes

on crushed dry ice or in liquid nitrogen.

16. Use a chilled, RNase-free spatula to transfer a small amount (up to 100 mg) of WT

frozen ground material to SIX of the new chilled 1.5 mL microcentrifuge tubes.

Use a scale to measure, but do not let the samples thaw. Keep the new tubes on dry

ice or in liquid nitrogen.

17. Use new chilled, RNase-free spatula to transfer a small amount (up to 100 mg) of

frozen ground material for each of the six mutant lines into the new chilled 1.5 mL

microcentrifuge tubes. Use a scale to measure, but do not let the samples thaw.

Keep the new tubes on dry ice or in liquid nitrogen.

18. Store the TWELVE aliquots in the –70°C freezer until the RNA extraction step. Also

store the remaining ground tissue for each sample in the –70°C freezer as a backup.

19. On the day of RNA extraction, prepare the RLC lysis buffer

c. Determine the total volume (= # of samples x 500 µL) of lysis buffer needed

for RNA isolation. Note: If the total volume is greater than 1.5 mL, it is best

to use a 14 mL centrifuge tube for preparing the lysis buffer with β-

mercaptoethanol.

d. Add 10 µL of β-mercaptoethanol to every 1 mL of lysis buffer in the fume

hood. Mix the contents in the tube by vortexing for 5 seconds. Put the tube

back on the rack.

Note: β-mercaptoethanol is toxic and has a bad odor. It is kept in the fume hood

in room 4128A2. The newly prepared lysis buffer with β-mercaptoethanol is

stable 1 month after the addition of β-mercaptoethanol.

Volume of RLC lysis buffer Volume of β-mercaptoethanol

mL µL


6.8

D. RNA Isolation

Materials Needed:

Ø 500 mL of freshly prepared 0.1% DEPC-treated water (non-autoclaved) for cleaning all equipment

Ø Kimwipes Ø Dewar flask or Styrofoam box Ø Liquid Nitrogen (from storeroom in Life Sciences Building) Caution: It is very cold

(at least -210°C). Avoid getting frostbite. Ø Aliquots of 1.5 mL RNase-free tubes containing ~100 mg of frozen powder from ground

up wild type Arabidopsis Columbia-0 siliques and siliques from each mutant plant (powder prepared by Teaching Assistants)

Ø Qiagen RNeasy Plant Mini Kit: (Cat. #74904 for 50 extractions) Ø β-mercaptoethanol. Caution: Work in the fume hood because this chemical has very

bad odor. Ø Autoclaved DEPC-treated (DEPC’d) water Ø P-10, P-20, P-200 & P-1000 pipettes Ø RNase-free filter tips for P-10, P-20, P-200 & P-1000 Ø Ice bucket Ø Black ultra-fine sharpie Ø RNase-free 1.5 mL microcentrifuge tubes Ø Racks for microcentrifuge tubes Ø Timer Ø NanoDrop spectrophotometer

Caution:

Ø All steps of the RNeasy protocol should be carried out at room temperature.

During the procedure, work quickly.

Ø All centrifugation steps are carried out at 20-25°C. Ensure that the centrifuge

does not cool below 20°C.

Ø Use filter pipet tips throughout the procedure.

Ø Change GLOVES frequently and keep tubes closed whenever possible.

PROCEDURE

Attention: Before isolating RNA, use Kimwipes wetted with freshly prepared non-

autoclaved DEPC treated water to clean all equipment (pipette sets, pipet stand,

microcentrifuge-tube racks, micro centrifuges and rotors, test-tube racks, pens and


6.9

sharpies, pipet tip boxes, microcentrifuge tube containers) to be used in isolating

RNA.

1. Locate TWO 1.5 mL microcentrifuge tubes containing a small amount (up to 100 mg) of frozen ground material from wild type or T-DNA-tagged siliques. These

will be stored on dry ice or in liquid nitrogen. Quickly, tap the tube on the bench or

the base of the vortex mixer 3-5 times to loosen the frozen powder.

2. Immediately, pipet 450 µL of RLC lysis buffer containing β-mercaptoethanol

into the 1.5 mL microcentrifuge tube containing ~100 mg of ground WILD TYPE

tissue. Cap the tube. Immediately, vortex the tube vigorously for at least 1 minute.

Then set the tube on a microcentrifuge tube rack. The lysate should appear clear with

no lumps of ground powder. (Optional) A short incubation time (1-3 minutes) at 56oC

may help to disrupt the tissue, but is NOT appropriate for organs rich in starch, such

as siliques or old leaves.

3. Repeat step 2 for the T-DNA sample.

4. Label the lids of TWO QIAshredder (lilac) spin columns placed in 2 mL collection

tubes with your initials and “WT” or “T-DNA.”

5. Pipet the entire volume of lysate into the labeled QIAshredder spin columns.

6. Centrifuge the spin columns in the collection tubes at FULL speed (13,200 rpm) for

2 minutes. Note: Centrifugation through the QIAshredder spin column removes cell

debris and simultaneously homogenizes the lysate. While most of the cell debris is

retained on the QIAshredder spin column, a very small amount of cell debris will

pass through and form a pellet in the collection tube Be careful not to disturb this

pellet when transferring the lysate to the new microcentrifuge tube.

7. Meanwhile, label the lids of TWO 1.5 mL RNase-free microcentrifuge tubes and

TWO RNeasy spin columns (pink) placed 2 mL collection tubes with your initials

and “WT” or “T-DNA.” Set the labeled tubes on a microcentrifuge tube rack at room

temperature.

8. Carefully transfer the supernatant of the flow-through solutions to the NEW labeled RNase-free 1.5 mL microcentrifuge tubes without disturbing the cell-debris

pellets in the collection tubes. Use only this supernatant in subsequent steps.


6.10

9. Add 0.5 volume (or 225 µL) of room temperature 96-100% ethanol to the WT

supernatant. Immediately, mix by pipetting up and down 10 times. Note: Do NOT

centrifuge. Proceed immediately to step 10.

10. Pipet the entire volume (~650 µL, but not more than 700 µL) of the WT mixture

(including any precipitate that may have formed) in step 9 to the “WT” labeled

RNeasy spin column (pink) placed in a 2 mL collection tube. Close the lid of the

tube gently.

11. Repeat steps 9 and 10 for the T-DNA mixture.

12. Centrifuge the spin columns placed in a 2 mL collection tubes for 15 seconds at

>10,000 rpm (or FULL speed).

13. Carefully remove the spin column from the collection tube so that the column does

not contact the flow-through. Hold the column with one hand and while pouring the

flow-through solution in the collection tube into a “waste” beaker. Be sure to empty

the collection tube completely. Put the column back in the collection tube. Note: If the

sample volume in step 10 is >700 µL, pipet the remaining volume of the mixture onto

the RNeasy column and centrifuge as before. Discard the supernatant.

14. Pipet 700 µL of Buffer RW1 to the RNeasy spin column. Close the tube gently.

15. Centrifuge for 15 seconds at >10,000 rpm (or FULL speed) to wash the spin column

membrane.

16. Carefully discard the flow-through as in step 13.

17. Pipet 500 µL of Buffer RPE into RNeasy spin column. Close the tubes gently.

18. Centrifuge for 15 seconds at >10,000 rpm (or FULL speed) to wash the spin column

membrane.

19. Carefully discard the flow-through as in step 13.

20. Pipet another 500 µL of Buffer RPE into the RNeasy spin column. Close the tube

gently.

21. Centrifuge for 2 minutes at >10,000 rpm (or FULL speed) to wash the spin column

membrane. Note: The long centrifugation dries the spin column membrane, ensuring

that no ethanol is carried over during RNA elution. Residual ethanol may interfere

with downstream reactions.

22. Label TWO new 2 mL collection tubes with your initials and “WT” or “T-DNA.”


6.11

23. Carefully transfer the columns to the new 2 mL collection tubes without allowing

the columns to contact the flow-through. Attention: At this point, total RNA and a

small amount of genomic DNA are bound to the membrane of the pink RNeasy spin

column.

24. Discard the flow-through solution and old collection tubes.

25. Spin the columns in the new 2 mL collection tubes for 1 minute to ensure that

ethanol is removed completely from the membranes. Caution: This step is crucial

because if residual ethanol is still on the membrane, it will be eluted with RNA in

steps 28-31.

26. Label the lids and sides of TWO 1.5 mL RNase-free microcentrifuge tubes “WT

RNA” or “T-DNA RNA,” your initials and the date.

27. Transfer the spin columns to these NEW labeled tubes.

28. Pipet 30 µL of RNase-free water (supplied with the kit) or autoclaved DEPC-treated

water directly onto the center of the column membrane. Close the tubes gently.

29. Wait for 1 minute to allow the membrane to evenly absorb the water.

30. Centrifuge for 1 minute at >10,000 rpm (or FULL speed) to elute RNA from the

membrane.

31. Repeat steps 28-30 with 20 µL of RNase-free water. Note: The total volume of RNA

solution is about 50 µL.

32. Mix the contents of the tubes with gentle flicking. Put tubes on ice. Note: From this

step on, KEEP RNA solutions ON ICE to prevent RNA degradation.

33. Determine the total volume of RNA solution using a P-200 pipette. The volume

should be ~48 µL.

34. Determine RNA concentration and total amount of RNA using the NanoDrop

spectrophotometer.

Total amount of RNA = (X µg/µL) (Volume of RNA solution in µL) = Y µg

Note: 1 µg = 1,000 ng; therefore, you need to convert ng/µL to µg/µL


6.12

Record RNA concentration and total amount of RNA

Sample [RNA]

(µg/µL)

Volume

(µL)

Estimated Total

Amount (µg)

Wild type siliques

T-DNA siliques

35. Label the lids and sides of TWO new RNase-free microcentrifuge tubes “1 µL WT

Silique RNA” or “1 µL T-DNA Silique RNA,” your initials and the date. Keep

tubes on ice.

36. Pipet 1 µL of the RNA solution into the new labeled tubes. These aliquots will be

used to assess the quality of the RNA in Part D. 37. Either keep the tubes on ice and proceed to Part C, or store the RNA solutions at -

20°C for up to 1 week or at -70°C for up to 6 months.

Attention: To be safe, only HALF of the volume of the RNA solution is treated with

RNase-free DNase; the remaining volume of RNA solution is kept on ice or stored in

the -20oC RNA freezer until the gel electrophoresis step in part D to determine

quality of RNA before DNase treatment.

C. Removing Contaminating Genomic DNA from Total RNA Solutions Using

RNase-free DNase

Reference: Turbo DNA-free kit protocol (Ambion; See Appendix 1H)

Important Note: This protocol is suitable for removing up to 2 µg of DNA from up to 20

µg of RNA in a 25-100 µL reaction volume.

Materials Needed: Ø 500 mL of freshly prepared 0.1% DEPC-treated water (non-autoclaved) for cleaning

all equipment


6.13

Ø Ice bucket Ø Total RNA isolated from wild type and mutant siliques Ø Ambion Turbo DNA-free kit (stored in RNA -20°C freezer; Cat. # 1907) Ø Turbo DNase (included in the Ambion Turbo DNA-free kit) Ø 10x Turbo DNase buffer (included in the Ambion Turbo DNA-free kit) Ø DNase inactivation reagent (included in the Ambion Turbo DNA-free kit) Ø Autoclaved DEPC-treated (DEPC’d) water Ø Black ultra-fine sharpie Ø RNase-free 1.5 mL microcentrifuge tubes Ø Rack for microcentrifuge tubes Ø 37°C heat block Ø Timer Ø Microcentrifuge Ø Vortex Ø P-10, P-20 & P-200 pipettes Ø RNase-free filter tips for P-10, P-20 and P-200 Ø White Revco storage boxes Ø Kimwipes Ø NanoDrop spectrophotometer PROCEDURE 1. Write down the concentration of the total RNA samples.

Note: 1 µg = 1,000 ng. Therefore, the concentration determined by the

NanoDrop spectrophotometer (ng/µL) needs to be converted into µg/µL.

WT T-DNA

RNA concentration µg/µL µg/µL

2. Determine the volume for 20 µg of total RNA.

Volume of 20 µg RNA = Amount of RNA ÷ concentration of RNA

Example: If total RNA has a concentration of 1.25 µg/µL, then the volume of 20 µg

of RNA will be 20 µg ÷ 1.25 µg/µL = 16 µL

WT T-DNA

Volume of 20 µg µL µL


6.14

3. Determine which volume is smaller for each sample: the volume of 20 µg of total

RNA or the volume of half of the isolated total RNA. Use the smaller volume in the

DNase reaction.


5. Remove your total RNA samples from the -20°C RNA freezer. Thaw on ice.

6. Label TWO 1.5 mL microcentrifuge tubes with “WT” or “T-DNA,” your initials and

the date. Set tubes on ice.

7. Add total RNA samples, DEPC’d water, 0.1 volume of 10x Turbo DNase buffer and

1 µL of 2 Units/µL Turbo DNase (Ambion) to the labeled, chilled tubes according

to the chart below. Make a master mix (Mmix) for the components that are shared in

both reactions. Note: One unit of DNase is defined as the amount of enzyme that

degrades 1 µg of DNA in 10 minutes at 37°C.

RNA Solution

WT Silique RNA

T-DNA Silique RNA

Mmix for 3 Reactions

RNA sample (up to 20 µg,

but not more than half of

your RNA)

X µL

DEPC’d water Y µL

10x Turbo DNase buffer 3.0 µL

Turbo DNase (2 Units/µL) 1.0 µL

Total volume 30.0 µL

X µL = volume of RNA sample; Y µL = volume of DEPC’d water

The volume of DEPC’d water is the difference between the total reaction volume and the

sum of the volume of the other components.

8. Mix the solutions gently by flicking the tubes. Spin briefly (5-10 seconds).

9. Immediately, store the tubes of remaining total RNA solution in a box at -20°C for up to 1 week or at -70°C for up to 6 months.

10. Incubate the DNase reactions at 37°C in a heat block for 20-30 minutes.


6.15

11. After incubation, spin tubes for 10 seconds in a microcentrifuge to bring water

condensation to the bottom of the tubes.

12. To inactivate Turbo DNase, pipet 0.1 volume (or 3.0 µL) of the DNase inactivation

reagent (WHITE slurry) to the sample using a P-20 pipet tip. Mix well by flicking the tube. Note: Make sure the slurry is WHITE. If the DNase inactivation reagent is

CLEAR, vortex the mixture for a few seconds.

13. Incubate the tube at room temperature for 5 minutes. Flick the tube 2-3 times

during the incubation to re-disperse the DNase inactivation reagent.

14. In the meantime, label the lids and sides of NEW RNase-free microcentrifuge tubes

“Purified WT Silique RNA” or “Purified T-DNA Silique RNA,” your initials and

the date.

15. Spin the tube at ~10,000 x g (or 10,400 rpm) for 1 minute to pellet the DNase

inactivation reagent.

16. Carefully, pipet ~28-30 µL of the RNA solution (AVOID pipetting the PELLET!)

and transfer it into NEW labeled RNase-free microcentrifuge tubes. Note: It is

okay if a tiny amount of the pellet is carried over in the RNA solution.

17. Keep RNA tubes on ice.

18. Determine the RNA concentration and total amount of RNA using the NanoDrop

spectrophotometer.

Total amount = (X µg/µL) × (volume of RNA solution) = Y µg

Note: 1 µg = 1,000 ng; therefore, you need to convert ng/µL to µg/µL

Samples

[RNA]

(µg/µL)

Volume

(µL)

Estimate Total

Amount (µg)

Purified WT Silique RNA

Purified T-DNA Silique RNA

19. Label the lids and sides of NEW RNase-free microcentrifuge tubes “1 µL Purified

WT Silique RNA” or “1 µL Purified T-DNA Silique RNA,” your initials and the

date. Keep tubes on ice.


6.16

20. Pipet 1 µL of the RNA solution into the new labeled tubes. These aliquots will be

used to assess the quality of the purified RNA in Part D.

21. Put the tubes of purified RNA samples back in a box at -20°C for up to 1 week or at

-70°C for up to 6 months. You may keep the 1 µL aliquots on ice if you will

proceed with Part D.

D. Determining the Quality of Isolated Total RNA Before and After DNase Treatment Using Capillary Gel Electrophoresis

Reference: RNA StdSens Analysis kit instruction manual (Experion, Bio-Rad)

Materials and Reagents Needed:

Ø 500 mL of freshly prepared 0.1% DEPC-treated water (non-autoclaved) for cleaning all equipment

Ø Kimwipes Ø Ice bucket Ø 1 µL aliquots of RNA samples before and after DNase Ø RNA StdSens Analysis kit (Experion, Bio-Rad) Ø RNA StdSens chip (Experion, Bio-Rad) Ø RNA StdSens ladder (Included in StdSens RNA Analysis kit) Ø RNA StdSens filtered gel (Included in StdSens RNA Analysis kit) Ø RNA StdSens gel-stain (Included in StdSens RNA Analysis kit) Ø RNA StdSens loading buffer (Included in StdSens RNA Analysis kit) Ø Electrode cleaner (Experion, Bio-Rad) Ø Autoclaved DEPC-treated (DEPC’d) water Ø Cleaning chips (Experion, Bio-Rad) Ø Black ultra-fine sharpie Ø RNase-free 1.5 mL microcentrifuge tubes Ø Rack for microcentrifuge tubes Ø 70°C heat block Ø Timer Ø Microcentrifuge Ø Vortex Ø P-10, P-20 & P-200 pipettes Ø RNase-free filter tips for P-10, P-20 and P-200 Ø Capillary gel electrophoresis system (Experion, Bio-Rad)


6.17

Note: A single StdSens RNA chip can hold 12 RNA samples. Three students may share

each chip and prepare one RNA ladder solution.

Note: Each 1 µl RNA sample should have a concentration of 5-500 ng/µl.

Note: Your instructor will prepare the gel-stain and clean the electrodes before samples

are run.

PROCEDURE

1. Equilibrate Experion RNA StdSens reagents (filtered RNA gel solution, RNA loading

buffer (yellow cap), gel-stain solution (amber tube)) to room temperature for at least

15 minutes. Place the kit in a drawer or dark room to keep the gel-stain protected

from light.

2. Set a heat block to 70°C.


4. Locate FOUR 1 µL aliquots of RNA samples before and after DNase. Thaw RNA

solutions on ice.

5. Spin the tubes of 1 µL RNA aliquots for 10 seconds in a microcentrifuge. Keep RNA

solutions on ice.

6. Remove a tube of 2 µL RNA ladder aliquot from the -70°C freezer. Spin the tube in

a microcentrifuge for 10 seconds to bring down any water condensation, and keep it

on ice.

7. Label a NEW 1.5 mL microcentrifuge tube “RNA ladder.” Keep the tube on ice.

8. Pipet 1 µL of RNA ladder into the new labeled 1.5 mL microcentrifuge tube.

9. Heat the FOUR tubes of 1 µL aliquots of RNA solutions and 1 µL aliquot of RNA

ladder on a 70°C heat block for 2 minutes. Note: It is okay to heat the samples for

up to 5 minutes.

10. Quench tubes on ice for at least 5 minutes.

11. Spin tubes in a microcentrifuge for 15-30 seconds. Keep tubes on ice.


6.18

12. Pipet 5 µL of loading buffer (yellow cap) to each RNA solution. Mix the contents

by flicking the tube several times. After adding the loading buffer to all RNA

solutions, spin tubes for 10 seconds. Keep the tubes on ice.

13. Remove an RNA StdSens chip from its plastic wrap. Using a P-10 pipette, pipet 9

µL of gel-stain into the well labeled GS with an orange highlight (third well from

the top). Note: To avoid bubbles, dispense reagents into chips slowly. Always insert

the pipet tip vertically and to the bottom of the chip well when dispensing liquids. Do

not expel air at the end of the pipetting step. This will reduce the possibility of air

bubbles becoming trapped between the reagent and the microchannels at the bottom

of the chip wells.

14. Put the chip on the priming station. Make sure the setting is B1.

15. Press the “START” button on the priming station. Wait for 30 seconds.

16. Open the priming station.

17. Pipet another 9 µL of gel-stain to the other well labeled GS (second well from the

top).

18. Pipet 9 µL of filtered gel into the well labeled G (top well).

19. Pipet 6 µL of the RNA mixtures prepared in step 12 into each sample well (1-4) and

into the ladder well (labeled L). Work quickly to minimize sample evaporation.

Note: Each chip can hold 12 samples. Therefore, three students can share one chip.

However, if there are only 4 samples, then pipet 6 µL of loading buffer into the

remaining wells (5-12). Caution: Do NOT leave any sample well empty.

20. Gently tap the chip on the bench 3-5 times to remove any bubbles present in the

sample wells. Inspect the wells for the presence of bubbles. Note: Run the chip

within 5 minutes of loading samples. 21. Place the sample-loaded chip on the platform of the electrophoresis station and close

the lid.

22. Launch the Experion software, select “New Run” and then “RNA StdSens.”

23. Select “Eukaryotic total RNA assay.”

24. Click the PLAY symbol button to begin the run. A window will pop up asking for the

total number of samples loaded. Type in number of samples and the software will


6.19

avoid the wells containing only loading buffer. The run will take up to 30 minutes for

all 12 samples.

25. While the electrophoresis is running, enter the sample information in the “data info”

tab.

26. After the run is complete, the analyzer beeps. Your TA will remove the chip from the

platform and discard the used chip.

27. Your TA will immediately place a cleaning chip containing 800 µL of DEPC’d

water on the platform. Close the lid of the electrophoresis system for 1 minute to

clean the electrodes.

28. Open the lid for 30 seconds to allow water to evaporate.

29. Remove the cleaning chip. Discard the water and store the cleaning chip for future

use.

30. Export data (electropherograms and gel images) to the desktop.

31. Copy the exported data on a USB flash drive and upload them onto the HC70AL server.

32. If there are no more runs for the day, your TA will turn off the electrophoresis system

and quit the Experion software.

33. Analyze the data.

What do you see in the picture?

What are the RNA fragments?

What are the sizes of RNA fragments?

Is there any difference in brightness between different samples before and after

DNase treatment?

What is the reason for the difference?


6.20

II. SYNTHESIZING FIRST STRAND cDNA USING REVERSE TRANSCRIPTASE

Purpose: To generate cDNA template for PCR analysis.

Reference: iScript cDNA Synthesis Kit Instruction Manual (Bio-Rad; See Appendix 1I)

Overview:

• The iScript reverse transcriptase is RNase H+, resulting in greater sensitivity

than RNase H- enzyme. iScript is a modified MMLV-derived reverse

transcriptase, optimized for reliable cDNA synthesis over a wide dynamic range

of input RNA.

• The enzyme is provided pre-blended with RNase inhibitor.

• The unique blend of oligo(dT) and random (6-bases, 8-bases, 10-bases) primers in

the iScript Reaction Mix works exceptionally well with a wide range of targets.

This blend is optimized for the production of targets <1 kb in length.

• iScript cDNA Synthesis Kit produces excellent results in both real-time and

conventional RT-PCR.

Caution: When using >1 µg of total RNA, the reaction volume should be scaled up to

ensure optimum synthesis efficiency. For example, use a 40 µL reaction for 2 µg.

Note:

Ø For each RNA sample, set up one reaction with Reverse Transcriptase (+ RT)

and one reaction without Reverse Transcriptase (- RT). The -RT sample serves as

a negative control for the PCR amplification step because without first strand

cDNA template, there will be NO PCR product with expected size observed.

However, if a PCR product is observed in the - RT sample, then RNA sample is

contaminated with genomic DNA.

Ø Work with master mixes as often as possible to prevent FALSE negative results

due missing components.


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Solutions Needed: Ø 500 mL of freshly prepared 0.1% DEPC-treated water (non-autoclaved) for cleaning

all equipment Ø Purified total RNA samples (after DNase, stored in -20°C RNA Freezer) Ø iScript cDNA Synthesis kit (Bio-Rad, Cat. #170-8890; stored in -20°C RNA Freezer) Ø iScript Reverse Transcriptase (included in iScript cDNA Synthesis kit) Ø 5x iScript Reaction mix (included in iScript cDNA Synthesis kit) Ø Nuclease-free water (included in iScript cDNA Synthesis kit) Ø Autoclaved DEPC-treated (DEPC’d) water

Materials Needed:

Ø Pipettes Ø RNase-free filter pipet tips Ø RNase-free 1.5 mL microcentrifuge tubes Ø Rack for 1.5 mL microcentrifuge tubes Ø Black ultra-fine sharpie Ø Ice bucket Ø Microcentrifuge Ø Vortex Ø Timer Ø 25°C heating block Ø 42°C heating block Ø 85°C heating block PROCEDURE 1. Write down the concentration of purified total RNA samples to be used.

Note: 1 µg = 1,000 ng. Therefore, the concentration determined by the NanoDrop

spectrophotometer (ng/µL) needs to be converted to µg/µL.

WT T-DNA

RNA concentration µg/µL

µg/µL

2. Determine the volume of 1 µg of purified total RNA.

Volume of 1 µg RNA = Amount of RNA ÷ concentration of RNA

Example: If the purified RNA has a concentration of 0.5 µg/µL, then the volume of 1

µg of RNA will be 1 µg ÷ 0.5 µg/µL = 2 µL


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WT T-DNA

Volume of 1 µg µL

µL

3. Use the following table as a guide to fill in the volumes for purified total RNA and

DEPC’d water.

Components RNA

+RT

RNA

-RT DEPC’d (or nuclease-free) water X µL X µL 1 µg Purified total RNA Y µL Y µL + RT Mix 5.0 µL - - RT Mix - 5.0 µL Total Reaction Volume 20.0 µL 20.0 µL

X µL = volume of RNA sample; Y µL = volume of DEPC’d water

The volume of DEPC’d water is the difference between the total reaction volume and

the sum of the volume of the other components.


5. Set heating blocks to 25°C, 42°C and 85°C.

6. Label the lids of FOUR RNase-free 1.5 mL microcentrifuge tubes “WT +RT,” “WT –RT,” “T-DNA +RT,” and “T-DNA –RT.” Keep tubes on ice.

7. Thaw the tubes of 5x iScript Reaction Mix and nuclease-free water at room

temperature. Once the solutions are thawed, spin tubes in a microcentrifuge for 10

seconds, and keep the tubes on ice.

8. Prepare TWO tubes for Master mixes (+RT Mix and -RT Mix) as follows:

g. Determine the number of RT reactions to be set up.

Note: # RT reactions = # of RNA samples + 1 Extra

Example: # RT reactions = 3 = WT Siliques + T-DNA Siliques + 1 Extra

h. Label the lids of the RNase-free microcentrifuge tubes “+RT mix” and “-RT

mix.” Keep the tubes on ice.


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i. Remove a tube of iScript Reverse Transcriptase from the -20°C RNA

freezer. Keep the tube on ice at all times to prevent degradation of the

enzyme in this tube.

j. Pipet the following components into appropriate tubes as shown below.

Components

+RT Mix for ONE

Reaction

+RT Mix for

3 Reactions

-RT Mix for ONE

Reaction

-RT Mix for

3 Reactions

DEPC’d (or nuclease-free)

water - - 1 µL 3 µL

5x iScript Reaction mix 4 µL 12 µL 4 µL 12 µL

iScript Reverse

Transcriptase 1 µL 3 µL - -

Total volume 5 µL 15 µL 5 µL 15 µL

k. Mix the contents by pipetting up and down five times or flicking the tubes

several times.

l. Spin the tubes in a microcentrifuge for 10 seconds. Put the tubes on ice.

9. Using the +RT and -RT chart written up in step 3, pipet the components into the

tubes labeled in step 6.

10. Mix the contents in each tube by pipetting gently up and down five times. Keep tubes

on ice.

11. Transfer all of +RT and -RT tubes from the ice bucket to either a heat block set to

25°C or a rack for microcentrifuge tubes on the bench (room temperature). Incubate

reaction tubes at 25°C (or room temperature) for 5 minutes. This step is to allow

oligo(dT) and random primers to anneal to the messenger RNA in the reactions.

12. Incubate the tubes at 42°C for 30 minutes in a heat block. This step is to synthesize

first strand cDNAs.

13. After 30 minutes at 42°C, inactivate reverse transcriptase, which is known to

interfere with Taq DNA polymerase in the PCR amplification step, by heating the

reactions at 85°C for 5 minutes in a heat block.

14. Chill the tubes on ice for at least 2 minutes.


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15. Centrifuge the tubes at room temperature for 1 minute to bring water condensation to

the bottom of the tubes. Note: The RT reactions are ready for the PCR amplification

step.

16. Store RT reactions in a -20°C freezer if they are not used for PCR the same day.

Otherwise, keep them on ice while setting up the PCR amplification step.


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III. CARRYING OUT PCR AMPLIFICATION (RT-PCR) ANALYSIS Purpose: To amplify the cDNA template corresponding to the mRNA for the gene of

interest in order to determine if the T-DNA insertion causes a null mutation (i.e. no

mRNA is expressed for the gene of interest).

Note: Amplification of tubulin cDNA will be used as a positive control because the

tubulin gene is expressed in all samples. Control primers are used to ensure that the

absence of a gene-specific PCR product in the +RT samples is NOT due to technical

mistakes.

Solutions Needed:

Ø Reverse transcription (+RT & -RT) reactions Ø Ex Taq DNA polymerase (Takara) Ø 10x Ex Taq buffer (Takara; comes with the Ex Taq DNA polymerase) Ø dNTP mix (Takara; comes with the Ex Taq DNA polymerase) Ø Sterile water Ø 12 µM Gene-specific RT Forward primer Ø 12 µM Gene-specific RT Reverse primer Ø 12 µM Tubulin Forward primer Ø 12 µM Tubulin Reverse primer Ø Agarose Ø 1x TAE buffer Ø 10,000x SYBR Safe DNA gel stain Ø 6x Loading buffer containing ONLY xylene cyanol Ø 100 bp DNA ladder (Invitrogen) Materials Needed:

Ø Pipettes Ø Filter pipet tips for PCR Ø Ice bucket Ø 0.2 mL PCR tubes Ø PCR tube rack Ø 1.5 mL microcentrifuge tubes Ø Microcentrifuge tube rack Ø Black ultra-fine sharpie Ø Microcentrifuge Ø Vortex Ø PCR machine (Bio-Rad MyCycler)


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Ø Gel electrophoresis materials (Appendix 1A) PROCEDURE


2. Determine how many RT reactions (including +RT’s and -RT’s and gene-specific

primers and control primers) will be amplified.

3. Make a table with information such as tube #, sample identity, +RT’s/-RT’s and primers (see the example table below).

Tube # Sample RT Primer set 1 WT Silique +RT Gene-specific RT 2 WT Silique -RT Gene-specific RT 3 T-DNA Silique RT Gene-specific RT 4 T-DNA Silique -RT Gene-specific RT

5 (Positive) Genomic DNA - Gene-specific RT 6 (Negative) Sterile Water - Gene-specific RT

7 WT Silique +RT Tubulin 8 WT Silique -RT Tubulin 9 T-DNA Silique RT Tubulin 10 T-DNA Silique -RT Tubulin

11 (Positive) Genomic DNA - Tubulin 12 (Negative) Sterile Water - Tubulin

4. Label the lids and sides of TWELVE 0.2 mL PCR tubes with the tube number and

your initials. Put the labeled tubes on a PCR tube rack sitting on ice.

5. Label the lids and sides of TWO 1.5 mL microcentrifuge tubes as “Gene-specific

Mmix” and “Tubulin Mmix.” Put the labeled tubes on ice.

6. Prepare a master mix for each primer set for the number of PCR reactions being

carried out plus 1 extra as follows:


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Gene-specific Mmix Components Mmix for ONE

Reaction

Mmix for

7 Reactions Sterile water 36.75 µL 257.25 µL 10x Ex Taq buffer 5.0 µL 35.0 µL dNTP mix 4.0 µL 28.0 µL 12 µM Gene-specific RT Forward primer 1.0 µL 7.0 µL 12 µM Gene-specific RT Reverse primer 1.0 µL 7.0 µL Ex Taq DNA Polymerase (5 U/µL) 0.25 µL 1.75 µL Total Volume 48.0 µL 336.0 µL

Tubulin Mmix Components Mmix for ONE Reaction

Mmix for 7 Reactions

Sterile water 36.75 µL 257.25 µL 10x Ex Taq buffer 5.0 µL 35.0 µL dNTP mix 4.0 µL 28.0 µL 12 µM Tubulin Forward primer* 1.0 µL 7.0 µL 12 µM Tubulin Reverse primer* 1.0 µL 7.0 µL Ex Taq DNA Polymerase (5 U/µL) 0.25 µL 1.75 µL Total Volume 48.0 µL 336.0 µL

* Control primers are used to ensure that the absence of a gene-specific PCR product in

the +RT samples is NOT due to technical mistakes.

7. Pipet 48 µL of master mix and 2 µL of sample into the appropriate labeled PCR

tubes according to the table in step 3. The total reaction volume should be 50 µL.

Mix the contents by pipetting gently up and down 5 times.

8. Carry out PCR on the Bio-Rad MyCylcer with the “HC70AL RT PCR” program

containing the following profile:

94°C 3 min

40 cycles of 94°C 10 sec

62°C 30 sec

72°C 45 sec

72°C 4 min

4°C ∞


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9. Prepare 100 mL of a 2% agarose gel in 1x TAE buffer using a 20-tooth comb.

10. Label TWELVE 1.5 mL microcentrifuge tubes according to the PCR reactions.

11. Add 20 µL of PCR solution and 2 µL of 6x loading dye with xylene cyanol only to

the labeled 1.5 mL microcentrifuge tubes.

12. Load 10 µL of 100 bp DNA ladder in the first well.

13. Load 20 µL of each sample-dye mixture on a 2% agarose gel using a P-20 pipette.

14. Record the identity of the sample in each lane.

Lane Tube Sample RT Primer set Expected Size (bp) 1 - 100 bp DNA ladder - - - 2 1 WT Silique +RT

Gene-specific RT

3 2 WT Silique -RT 4 3 T-DNA Silique +RT 5 4 T-DNA Silique -RT 6 5 Genomic DNA - 7 6 Sterile Water - - 8 7 WT Silique +RT

Tubulin

9 8 WT Silique -RT 10 9 T-DNA Silique +RT 11 10 T-DNA Silique -RT 12 11 Genomic DNA - 477 13 12 Sterile Water - - 14 - 100 bp DNA ladder - - -

15. Add 10 µL of 10,000x SYBR Safe DNA gel stain to the running buffer at the anode.

16. Run the gel at 105 volts for 1-2 hours or until the front dye (bromophenol blue)

travels about two-thirds of the gel.

Time power supply turned ON:

Time power supply turned OFF:

How long was the gel run? ______ hour(s) and _______ minutes

17. Take a picture of the gel using the Bio-Rad Gel Document System.

18. Print out the picture. Store the labeled picture in your lab notebook.

19. Analyze the data.

How many DNA fragments do you see on the gel?


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What are the sizes of the DNA fragments?

What is the size of the PCR product corresponding to the mRNA of the gene of

interest?

What is the expected size of the PCR product for genomic DNA?

Is there a difference in size between the PCR products from cDNA and genomic

DNA?

Is there difference in brightness between the PCR products from wild type siliques

and mutant siliques?

What can you conclude about the expression of the gene of interest?

Are the RT-PCR results correlated to the GeneChip data?

EXPERIMENT 6 – RNA ISOLATION AND RT-PCR ANALYSIS ...

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